Interlocking system for railroads



June 1, 1937. s. N. WIGHT INTERLOCKING SYSTEM FOR RAILROADS Filed Feb.27, 1930 2 Sheets-Sheet 1 1 E H t 0H ow-l lNVE TOR ATT NEY June 1, 1937.s. N. WIGHT INTERLOCKING SYSTEM FOR RAILROADS Filed Feb. 27, 1950 2Sheets-Sheet 2 kfinllllmulllllflllll||nulullmlll|IIIIIMllllllln|m|\lllIlllllllllmlillllllllllllnunllllllllnlllllllllllllllllllilllllmllllllllllll' Patented June 1, 1937 UNITED STATES PATENT OFFICEINTERLOCKING SYSTEM FOR RAILROADS Sedgwick N. Wight, Rochester, N. Y.,assignor to genYeral Railway Signal Company, Rochester,

Application February 27, 1930, Serial No. 431,748

35 Claims. (01. 246-135) This invention relates to manually controlledpower operated interlocking systems for railroads, and more particularlyto a system of remote control for a power-operated switch machine.

This application is a continuation in part of my prior application Ser.No. 257,643 which matured into Patent No. 1,759,383 dated May 20, 1930.

One object of the present invention is to provide a simple and novelorganization of parts and circuits to obtain the necessary or desirablecontrols and indications for a power-operated switch and its associatedsignals.

Another object of the invention is to provide simple electrical meansfor approach and detector locking control, which requires movement ofthe control lever while the approach and detector locking devices areenergized, without mechanically restraining the movement of the controllever.

or representative of a simple facing point switch, frequentlyencountered in track layouts for interlocking plants; and an explanationof the invention, applied to such a switch, will readily demonstrate tothose skilled in the art how the invention may be applied to double slipswitches, movable point frogs, cross-overs, and other track combinationsencountered in practice.

The switch machine SW is operated by a suitable power switch machine SM;and it is assumed that this switch machine is of the electricallyoperated type, such as disclosed, for example, in the patent to W. K.Howe, No. 1,466,903, dated Sept. 4, 1923. The operating current for thisswitch machine is derived from a local battery 13, or other suitablesource of direct or alternating current, in accordance with thecharacteristics of the switch machine. The application of operatingcurrent from the battery B to the switch machine SM, overnormal andreverse operating Another object of the invention is to simplify wires 3and 4, is controlled by a suitable polarized 20 and facilitate themanipulations of the operator three-position remote control relay E. Ifdirect by providing such correlation between the track current isemployed for the control of the switch diagram, the control levers,- andindicators, as machine, as in the particular embodiment shown, willenable the operator to manipulate the levers this remote control relay Emay be of the three- 25 effectively with the minimum amount of effort.position D. 0. motor type, such as disclosed, for Other objects,characteristic features and adexample, in the patent to W. K. Howe etal., No. vantages of the invention will be in part apparent 1,180,719,dated April 25, 1916. If alternating to those skilled in the art, and inpart pointed out current is available and employed for theconhereinafter, as the description progresses. trol of the switchmachine, this remote control 30 In the accompanying drawings, Fig. 1shows in relay E may be of the three-position two-element a diagrammaticand simplified way one specific alternating current induction type, suchas disembodiment of the invention applied to the conclosed, for example,in the patent to S. M. Day No. trol of a single track switch and signalsfor di- 1,624,478, dated April 12, 1927. The detail converging routesgoverning traific over this switch; struction of this remote relay formsno part of Fig. 2 shows the form of track diagram conthis invention, andmay take various forms, so templated in accordance with this invention,long as provision is made for the closing of its with the disposition ofthe switch and signal connormal contacts, when this relay is energizedover trol levers, as applied to a simple track layout; the control wires5 and 6 with one polarity, close n and its reverse contacts whenenergized with the op- 0 3 ShOWS a 0 fi at o a aptation of t e positepolarity, and for maintaining closed either embodiment of the inv tio uat d in 1. its normal or reverse contacts when deenergized, Referring to1 0f the a p y ng draW- until energized with current of the oppositeings, the principles and functions of the invenpolarity. In other words,this remote control 4-5 tion are exemplified by one specific embodimentrelay E, is of the stick type, and its contacts are applied to a singleswitch, the various devices held in some suitable manner, by friction,spring, and circuits being illustrated conventionally and permanentmagnet, toggle levers, or the like, in in a diagrammatic manner, morewith the object an operated position until operated to the other ofmaking it easy to understand the nature and position. mode of operationof the invention, rather than In accordance with this invention, theswitch 50 with the purpose of showing specifically the detailconstruction and arrangement of parts preferaoly employed in practice.The stretch of track TK, the switch SW, and the signals l and 2,governing trafiic over this switch, are typical machine SM is equippedwith suitable point detector contacts, operated in accordance with theposition and locked condition of the switch points. A point detector,suitable for this purpose, is shown and described, for example, in thepatent to C. S. Bushnell, No. 1,517,236, dated Nov. 25, 1924. In Fig. 1,the contacts of this point detector PD are shown diagrammatically andcomprise four pairs of contact fingers 1-40, and two movable contactblocks II and I2. When the switch points are over and locked in thenormal position, as shown, the contact blocks II and I2 engage the pairsof fingers 9 and I; and when the switch points are over and locked inthe 0 other extreme reverse position, these contact blocks engage theother pairs of contact fingers 'I and 8. When the points are unlocked orin mid-stroke, the contact blocks H and 12 are operated to anintermediate position out of engagement with all of the contact fingers.These point detector contacts PD also preferably include shuntingcontacts, comprising movable arms l3 and i4 and cooperating stationarycontacts l and "5. With the points in the normal locked position, theshunting contacts l3-l5are open, and the shunting contacts l4-H5 areclosed. In the reverse position, just the opposite is true, thatis,contacts I3-l'.i are closed and contacts I l-l5 are open. While theswitch 4 points are unlocked or in mid-stroke, both the shuntingcontacts 13-45 and 14-46 are closed. A suitable source of current, as abattery 11, and a pair of control wires [8 and 19, are connected tothese point detector contacts PD, pro- 0 viding for the energization,with one polarity or another, or the deenergization and shunting, of aswitch repeating or signal selecting relay SS located in the tower.

The track rails of the stretch of main track TK and the turn-out track,together with the switch points, are provided with insulated joints andcross bonding to provide a detector track circuit having a track relayT, in accordance with well known practice. This track relay T controls atrack repeater relay TR, located in the tower, over a circuit readilytraced on the drawings from one terminal of a suitable source ofcurrent, indicated by to the other terminal of that source, indicated by5 The stretch of main track TX, in the rear of the switch and signals land 2, is also provided with suitable track circuits, two of which withtrack relays and 2! having been shown. A distant signal 22 is alsoillustrated, the track circuit for the track relay 2| being associatedwith the track section next in the rear of the distant signal 22.

The tower equipment, shown in the left hand part of Fig. 1, comprises asuitable track diagram, such as shown more fully in Fig. 2. This trackdiagram includes the usual wide lines indicating the tracks of the tracklayout for the plant, but the track switches are pivoted members,movable by an electro-magnetic device to positions 0 corresponding tothe normal and reverse positions of the switch. More specifically,referring to Fig. 1, the member or miniature switch 23,

representing the switch SW on the track diagram, is pivoted at 23*, andis operatively con- 5 nected in some suitable manner, indicated by adotted line, to the armature 24 of two electro-magnets 25 and 25, sothat when the elec tro-magnet 25 is energized, the miniature switchpoint 23 is moved to the normal position as 0 shown, and'if the othermagnet 26 is energized, it is moved to the reverse position. On thetrack diagram, at the point corresponding to the location of the severaltrack circuits, is an indicator lamp TI, which is lighted when thecorrespond- 5 ing track circuit is occupied. For example, re-

ferring to Fig. 1, the lamp TI is energized by a circuit including theback contact 21 of the track repeater relay TR, so that whenever thedetector track circuit for the switch SW is occupied, the lamp TI islighted.

Also preferably located on the track diagram, at the propercorresponding point, are knobs or handles for operating the contactscontrolling the signals. For example, referring to Fig. 1, a knob SC- isemployed for controlling the signals l and 2. This knob is suitablyconnected, as indicated by dotted lines, to a contact 28, closed whenthis knob is turned to the right, as indicated by the arrow 29,preferably marked on the track diagram. This knob SG also preferablycarries an arrow, or other suitable symbol, to show its position. Asshown, when the arrow on this knob SG points cross-wise of the lineindicating the track, the contact 28 is open, and the signals I and 2indicate stop; is turned to the right, so that this arrow pointslengthwise of the line indicating the track and toward the miniatureswitch 23, the contact 28 is closed, controlling the signals 1 and 2 tocause one or the other to clear, depending upon the position of thepoints of the switch SW, and the presence or absence of trains. Ifdesired, this switch SG may have two contacts associated therewith oneof which is closed when the arrow points up which may be included in thecircuit for the signal i and the other of which is closed when the arrowpoints down included in the signal 2, so that the arrow may indicatewhether a high or low signal is conditioned for clearing. Similarly, thearrow may indicate the contemplated direction of traffic movement onsingle track railroads where trains move in both directions.

The control levers L for the several switches are preferably located, asnearly as possible, directly below the corresponding switch on the trackdiagram. For example, referring to Fig. 1, the lever L controlling theswitch SW is located directly below the miniature switch point 23. Thislever L is shown diagrammatically and is movable from the normalposition shown, to a reverse position, indicated by dotted lines; andthis lever is connected in a suitable manner, indicated by dotted lines,to a plurality of contact fingers 30-43, likewise movable from oneextreme position to the other into and out of engagement with contactsindicated conventionally as arrows, with the exception of the contactfinger 32, which engages a stationary contact 32 during a portion of themovement of the lever at its intermediate position, for the purposeshereinafter explained.

Associated with each switch control lever L is a lamp AL to indicate thepresence or absence of trains, or other conditions, permitting orpreventing operation of the switch. A lamp S, energized through a backcontact 35 of the switch repeating relay SS, indicates when the switchmachine is operating.

Also associated with the lever L in the tower is a slow release relayLP, and a relay LR for approach locking. This relay LP although slowrelease has preferably a quick pick-up characteristic, so that it willpick up even though the lever L is moved quickly from one extreme to theother extreme position. This may be accomplished by providing suitableretarding means delaying the opening of the contact such as a dash-potor a coil on the relay short circuited only when the relay is in itsattracted condition.

Operation.Considering now the operation of and when the knob theembodiment of the invention shown in Fig. l, the parts and circuits areshown in the "normal condition, corresponding to the switch SW in thenormal position and the signals I and 2 indicating stop. Under theseconditions, the switch repeating relay SS is energized with one polarityover a circuit from the battery I! through the point detector contactsPD which may be traced in detail as followsz-from the terminal of thebattery l1, wire 40, contacts 9-| l, wire 4|, control wire l8, backcontact 42 of the relay LP, wire 43 of the relay SS, control wire l9,shunt contacts |4|6, wire 44, contacts ||J|2, and'wire 45 back to theother terminal of the battery I1. I

With the switch repeating relay SS energized with this polarity ofcurrent, its armature is attracted closing its front contact 46, andcausing its polar contact 41 to assume the normal position shown andready to establish the control circuit for the signal I, this controlcircuit being'connected in a manner not shown to a suitable relaygoverning the indications of the signal subject to the automatic blocksignal circuits governing the indication of that signal, in accordancewith the presence of trains in advance of it.

Under the norm'alconditions assumed, the operator may clear the highspeed signal I by turning the knob SG to close the contact 28, whereuponcurrent may fiow from through contact 28, wire 48, front contact 46 ofthe relay SS, wire 49, polar contact 41 of relay SS normal, and thenceover the control circuit for signal I, clearing this signal if there areno trains ahead, and no conflicting route is established. It should beunderstood, in this connection, that the control circuit for the signalI includes contacts of the switch repeating relay SS associated witheach and all of the switches in the routes governed by this signal I,and in any conflicting routes, in accordance with the recognizedpractice.

Assuming that the operator desires to set up a new route through theplant, and in tracing this new route on the track diagram, finds thatthe particular switch SW, shown in Fig. 1, should be put in the reverseposition. If no train has entered the approach locking limits since thelast train movement over the switch SW, the track relays and 2| areenergized, and the approach locking relay LR is energized by its stickcircuit which may be traced from through the front contact 50 of thetrack relay 20, wire 5|, front contact 52 of track relay 2|, wire 53 tothe tower, relay LR, wires 54 and 55, front contact 56 of relay LR, to

The relay LR, being thus energized, opens its back contact 51 and anindicator lamp AL is extinguished, indicating to the operator that theapproach locking permits operation of the switch SW in question.Obviously, the lamp AL may be lighted through a front contact of therelay LR, so that this lamp indicates, when lighted, that the switch maybe operated, rather than when extinguished.

If there is no train present on the detector track circuit for theswitch SW, the track relay repeater TR is energized and the trackindicator lamp TI is extinguished. The control of this indicator lamp TImay of course be reversed, without departing from the invention, so thatit is lighted, when the detector track circuit is unoccupied, ratherthan extinguished.

After noting from these indicator lamps TI and AL that the switch SW maybe properly operated to the reverse position, the operator moves hislever L from the normal position shown to the reverse position. Inpassing through the intermediate position, the lever contacts 32-32 areclosed for a short interval of time; and since the relays TR and LR areassumed tobe energized, an energizing circuit for the relay LP isestablished'as follows: from front contact 600i moveits contactfingers65 and 66 from the lower position, as shown, to the upper position; andon account of the slow releasing characteristic of this relay LP, itsfront contacts are maintained closed for a short interval of time,during which the remote control relay E is energized from the towerbattery 10, through the lever contact fingers -3fl-3|, as can be readilytraced on the drawings. The time of dropping the relay LP is of coursesuch that the relay E has time to respond. This energization of theremote control relay E, with reverse polarity, causes "the switchmachine to operate the switch points to the reverse position.

As soon as the relay LP is energized, by movement of the lever L in themanner just explained, the opening of its back contact 42 deenergizesthe switch repeating relay SS, opening its front contact 46, so as toprevent the clearing of the signals and 2, and closing its back contact35. so as to light the indicator lamp S. As soon as the switch pointsare unlocked, the contact blocks H and I2 of the point detector contactsPD assume an intermediate position, cutting oil the battery I! from thecontrol wires |8--|9, so as to maintain the relay SS deenergized. Also,while the switch points are unlocked or in mid-stroke, both of theshunting contacts |3--|5 and |4-|6 are closed, thereby providing a shortcircuit for the two control wires Hi and i9, comprising wires II and 12,so as. to deenergize the relay SS, even though stray potential may beapplied to these control Wires.

After the switch machine has completed its cycle of operation, and thepoint detector contacts PD have shifted to the reverse position, therelay SS is again energized, but with the opposite polarity, the relayLP in the meantime having closed its back'contact 42. This energizationof the relay SS opens its back contact and extinguishes the indicatorlamp S, thereby informing the operator that the switch has operatedproperly as intended."

It will be observed that the indicator lamp S is lighted while theswitch machine is operating; and if it should remain lighted, theoperator knows that the switch points have encountered some obstruction,or something else has happened to prevent its regular operation.

With the switch SW operated to the reverse position in this manner, theoperator may then clear the low speed signal 2 by operating the knob SGto close itscontacts 2B, the control circuit for the signal 2 beingestablished in this case, because the polar contact 41 of the relay SShas been reversed.

It should be noted that current can not be applied to the remote controlrelay unless the relay LP is energized, the connection between thecontrol Wires 5 and 6 through the lever contacts 30 and 3| to thebattery 70 being broken at the ill) front contacts 6566 of the relay LP.The wires 36 and 31, connecting the back points of the relay LP of theopposite control wire 5 or 6 are preferably employed to provide twoshunts or short circuits for these control wires, so as to preventenergization of the remote control relay by stray currents applied tothe control wires through crosses or grounds, while the relay LP isdeenergized. Moreover, the relay LP is energized temporarily, duringmovement of the lever from one position to the other, providing thedetector and approach locking permits such energization. In other words,there must be a movement of the controllever L for the switch, each timebefore current can be supplied to the remote control E to change theposition of the switch.

Thus, the relay LP provides the desirable characteristics of a leverlock, mechanically restraining movement of the control lever, because nooperation of the switch machine occurs unless the lever is moved whileor as the detector and approach locking relays are energized. Thisprevents abnormal or unexpected operation of the switch, which mightoccur if the operator should carelessly or accidentally leave hiscontrol lever in the wrong position, while the approach or detectorlocking is effective. In such a case, if it were not for the relay LP,as soon as the detector and approach locking relays became energized,the switch would operate into position corresponding with the positionof the lever, and such operation might be unintentional and unexpected.

The electro-magnets 25 and 26, operating the F miniature switch point 23on the track diagram,

are shown in Fig. 1 as energized through the lever contact 33 in thenormal and reverse position. With this arrangement, the miniature switchpoint 23 follows the movements of the control lever L,irrespective ofthe position of the corresponding track switches. This is considereddesirable, because the operator can readily tell from his track diagramwhat route has been set up by the movement of the control levers; and

. if the indicator lamps S on the track diagram are all extinguished, heknows that the track switches are in positions corresponding with theposition of the middle switches, and that the desired route has actuallybeen set up, making it possible to clear the signals.

The miniature switch point 23, however, may be operated so as toindicate the position actually assumed by the corresponding trackswitch. This is done by controlling the circuits for the electro-magnets25 and 26 through polar contacts on the switch repeating relay SS, asshown in Fig. 3. With this arrangement, the operator knows that, whenthe indicator lamp S is extinguished (or lighted if the reversearrangement is employed) the switch points are over and locked in thesame position indicated by the miniature switch 23.

The control of the approach locking relay LR may take various forms,such as described, for example, in my prior application, Ser. No.48,553, filed August 6, 1925. In the simple arrangement shown, thisrelay LR is deenergized upon the entrance of a train into a tracksection next in the rear of a distant signal, and so long as this trainis in the rear of the home signal. Thus, if a train is approaching theswitch SW, the relay LR is deenergized, the relay LP cannot be energizedand the switch cannot be operated, even though the operator should causethe signals l and 2 to indicatestop by operation of thesi'gnal controlknob SG. .As shown, the relay LR, once contact 15 of the track relayrepeater TR, providing the track relays 20 and 2| of the approachlocking zone are energized.

Having thus shown and described one specific embodiment of theinvention, it is desired to be understood that the particular embodimentselected has been selected for the purpose of exemplifying the inventionand is not intended to show the scope of the invention or the exactconstruction preferably employed in practicing the invention, and it isalso to be understood that various additions, changes and modificationsmay be made to adapt the invention to the particular problem encounteredin practicing the same, all without departing from the spirit or scopeof the invention, except as demanded by the scope of the followingclaims.

What I claim as new is:

1. In an interlocking system for railways, the combination with a switchand signal layout including a track switch and a switch machine for'operating the track switch, a relay of the stick type for controllingsaid switch machine, a circuit for said relay, a 1ever,,and meansassociated withsaidlever permitting closure of said circuit for alimited time only upon movement of said lever.

2. In an interlocking system for railways, the

combination with a switch machine for operating .a track switch, a relayof the stick type for controlling said switch machine, a circuit forsaid relay, a lever, a locking relay, and means associated with saidlever permitting closure of said circuit only if said lever is moved ata time when said locking relay is energized.

ing relay is energized at the time of such lever movement.

'4. In an interlocking system for railways, the combination with aswitch and signal layout including a track switch and a switch machinefor operating the track switch, a relay of the stick type forcontrolling said switch machine, a circuit for said relay, a lever, aslow-dropping relay having a front contact included in said circuit, anda lever which in one position energizes said slow dropping relay and inanother position closes said circuit.

5. In an'interlocking system for railways, the combination with a switchand signal layout including a track switch and a switch machine foroperating the track switch, a relay of the stick type for controllingsaid switch machine, a circuit for said relay, a lever, means associatedwith said lever permitting closure of said circuit only if saidlever'assumes two specific positions in less thana predetermined time, aminiature track switch associated with said lever, and electroresponsivemeans for operating said miniature of the stick type for controllingsaid switch machine, a circuit for said relay, a lever, and meansassociated with said lever permitting closure of said circuit only ifsaid lever assumes two specific positions in less than a predeterminedtime, a miniature track switch associated with said lever,electro-responsive means for operating said miniature track switch,means for controlling said electro-respo-nsive means in accordance withthe position assumed by said lever, and means for indicating if saidswitch is over and locked in one position or the other.

7. In an interlocking system for railways, the combination with a switchand signal layout including a track switch and a switch machine foroperating the track switch, a relay of the stick type for controllingsaid switch machine, a circuit for said relay, a lever, a slow-droppingrelay having a front contact included in said circuit, a back contact onsaid slow dropping relay for shunting said first mentioned relay, and alever which in one position energizes said slow dropping relay and inanother position closes said circuit.

8. In an interlocking system for railways, the combination with a switchand signal layout including a track switch and a switch machine foroperating the track switch, a relay of the stick type for controllingsaid switch machine, a circuit for said relay, approach locking means insaid circuit for preventing operation of said switch machine during theapproach of a train, a lever, and means controlled by said approachlocking means and responsive to the movement of said lever forconnecting said relay circuit to said lever for a limited time onlyafter movement of the lever.

9. In an interlocking system for railways, the combination with a switchand signal layout including a track switch and a switch machine foroperating the track switch, a relay of the stick type for controllingsaid switch machine, a circuit for said relay, approach locking means insaid circuit for preventing operation of said switch machine during theapproach of a train, a lever, and means rendered elfective by movementof said lever only if said locking means is then ineffective foroperatively connecting said circuit to said lever for a limited time.

10. In an interlocking system for railways, the combination with aswitch and signal layout including a track switch and a switch machinefor operating the track switch, a relay of the stick type forcontrolling said switch machine, a circuit for said relay, approachlocking means in said circuit for preventing operation of said switchmachine during the approach of a train, a lever, and a slow-releasingrelay energized temporarily upon movement of said lever only if saidlocking means is then ineffective for connecting said circult to saidlever for a limited time.

11'. In an interlocking system for railways, the combination with aswitch and signal layout including a track switch and a switch machinefor operating the track switch, a relay of the stick type forcontrolling said switch machine, a circuit for said relay, a lever, aslow-dropping relay, a front contact of said slow-dropping relayincluded in said circuit, a back contact on said slow-dropping relay forshunting said first mentioned relay, and a lever which in one positionenergizes said slow dropping relay and in another position closes saidcircuit.

12. In an interlocking system for railways, the combination with aswitch and signal layout in position or the other,

eluding a track switch and a switch machine for operating the trackswitch, a relay of the stick type for controlling said switch machine, acir-' cuit for said relay, approach locking means in said circuit forpreventing operation of said switch machine during the approach of atrain, a lever, and means associated with said lever permitting closureof said circuit only if said lever type for controlling said switchmachine, a circuit for said relay, approach locking means in saidcircuit for preventing operation of said switch machine during theapproach of a train, a lever, means associated with said leverpermitting closure of said circuit only if said lever is operated at atime when said locking means is not effective,

a miniature track switch associated with said lever, electro-responsivemeans for operating said miniature track'switch, and means forcontrolling said electro-responsive means in accordance with theposition assumed by said track switch. 14. In combination, arailwaytrack layout, a miniature track layout corresponding to said railwaytrack layout, a rotatable control button located in the track of saidminiature track layout, contacts associated with said button forcontrolling said signal, and an indicia on said'but-' ton for indicatingthe direction of trafiic permitted by said signal when said buttonassumes the signal clear position. 15. In a system for governingpower-operated switches the combination with a switch machine, a controllever, a track diagram positioned adjacent said lever and including amovable miniature switch point, electro-responsive means governed inaccordance'with the position. of said lever for actuating said switchpoints, and indicating means automatically governed by the switchmachine for indicating when the points of said track switch are over andlocked inone 16. A controlling system for power-operated switchescomprising, a control lever, a' switch position indicator governed bysaid lever, a polarized indication circuit controlled by the switchmachine, and a transit lamp controlled by said circuit.

17. In a trafiic controlling system for railroads, a switch machine, acontrol circuit for said switch machine, a free and non-lockable controllever for governing the energization of said circuit, a locking relayresponsive to the presence of trains adjacent said switch,'and means forrendering said lever effective to govern the energization of saidcircuit at any time thereafter only if said lever is shifted to adifierent position at a time when said locking relay is energized.

18. In a trafiic controlling system for railroads, the combination witha power-operated switch machine, a polarized control circuit, a remotecontrol relay governed by said circuit and remaining in its lastenergized position until energized with current of opposite polarity, atrack circuit controlled locking relay, and means including a manuallyoperable control lever for momentarilyenergizing said control circuitwhen said lever is shifted to a different position at a time when saidlocking relay is energized.

19. A control system for power operated switch machines for railroadscomprising, a switch machine, a control circuit for said switch machine,a lock relay having a front contact included in said control circuit, acontrol lever having contacts included in said control circuit and inthe circuit of said lock relay respectively of which only one contactcan be closed at one time, and a trafific controlled contact included insaid circuit of said lock relay, whereby said control circuit can beenergized only if said traffic controlled contact is closed just priorto movement of said lever to a position to close said control circuit atthe lever contact.

20. A control system for power operated switch machines for railroadscomprising, a control circuit for such switch machine, a lock relayhaving a front contact included in said control circuit, a control leverhaving contacts included in said control circuit and in the circuit ofsaid lock relay respectively of which only one contact can be closed atone time, and a traflic controlled contact in series with one of thesaid contacts of said lever.

21. In a railway control system, a track layout, a miniature diagram ofsaid track layout, manually operable contact means so associated withsaid miniature layout to simulate various conditions of trafficcontrolling devices thereof and control means effective to conditionsaid traffic controlling devices in accordance with the manuallyselected contact means.

22. In a control system for power operated switch machines, incombination with a switch machine and a track switch operable thereby, adistant central control office, a miniature track switch at the controloffice, a line circuit connecting the control oflice with the switchlocation, electromagnetic means at the control oilice which if energizedin one manner will cause the miniature switch to be actuated to oneextreme position and if energized in another manner will cause saidminiature switch to be actuated to a different extreme position, and arelay distinctively controlled over the line circuit in accordance withthe position assumed by the track switch and controlling distinctiveenergization of the electro-magnetic means.

23. In a system for the remote control of power-operated switches, thecombination with a track diagram having a movable miniature switch pointto indicate the position of a distant switch, a polarized indicationcircuit having its continuity and polarity governed in accordance withthe locked condition and position of the track switch, a polar relay insaid indication circuit, electro-responsive means distinctivelyenergized in accordance with the polarity of energization of said polarrelay for automatically magnetically actuating said miniature switch toa position corresponding with the position of the distant track switch,and an indicating lamp controlled over said indication circuit forindicating when said switch is in mid-stroke.

24. In combination, a distant traffic controlling device; a two positionrelay constructed to respond to a momentary flow of current and toremain in its last operated position until operated to another positionfor controlling said device; a lever for controlling said relay butnormally ineffective to directly control said relay; and means forpermitting control of said two position relay by said lever including, aslow acting relay having front contacts included in the circuit of saidtwo position relay, and means for energizing said slow acting relay fora time in response to the act of changing the position of said lever.

25. In combination, a railway trafiic controlling device having a normaland an abnormalcondition, a free lever operable to two extreme positionsand tending when in one position to cause said traffic controllingdevice to be operated to the normal condition and when in the otherposition tending to cause said traiiic controlling device to be operatedto the abnormal condition, traffic controlled means for preventing saidlever from controlling said traffic controlling device so long astraffic conditions are unfavorable, and other means for preventing saidlever from controlling said traiiic controlling device in response toclearing up of said unfavorable traffic conditions unless said lever isoperated after such clearing up of trafiic conditions.

26. In combination, a railway traffic controlling device having a normaland an abnormal condition, a free lever operable to two extremepositions and tending when in one position to cause said trafficcontrolling device to be operated to the normal condition and when inthe other position tending to cause said traiiic controlling device tobe operated to the abnormal condition, and other means for preventingcontrol of said traffic controlling device by said lever under certaintraffic conditions and thereafter irrespective of traffic conditionsunless said lever is operated after traffic conditions have againchanged.

27. In combination, a track layout including a track switch forestablishing any one of a plurality of routes, a switch machine foroperating said track switch, a polar control circuit for controllingsaid switch machine to a normal position and to the reverse positionrespectively when energized by current of one polarity or the other, alock relay having front contacts included in said polar control circuit,whereby said switch machine cannot be operated to either position unlesssaid lock relay is energized, a signal for governing trafiic over one ofsaid routes, and a circuit which must be closed to permit clearing ofsaid signal and including back contacts of said lock relay closed onlyif said lock relay is deenergized.

28. In combination, a railway track switch, a switch machine foroperating said track switch, a lock relay which must assume itsenergized position for each cycle of operation of said switch machine topermit such switch machine to operate said track switch and which doesnot select the direction of operation of said switch machine, a signalfor governing traffic over said switch, and a circuit which must beclosed to per mit clearing of said signal including in series a contactreflecting the position of said track switch and a back contact of saidlock relay.

29. In a remote control system, an office and a station, a railway trackswitch and signals for governing the movement of traific over theswitch; a switch control circuit comprising a switch control relay atthe station, line wires and contacts of a switch lever at the office andadapted to be closed to energize the relay to operate the switch; asignal control circuit comprising line wires and contacts of a signallever at the ofiice and adapted to be closed in certain positions of thesignal lever to selectively clear said signals; a contact at the officeincluded in said signal control circuit; a switch indication relay atthe oflice; adapted to indicate the condition of the switch; and meanscontrolled by the switch when fully operated to energize the switchindication relay, said contact being controlled by said switchindication relay and when closed to thereby render the signal circuitresponsive to the condition of said signal lever contacts.

30. In a system for the remote control of power-operated track switchesand signals on railroads, a control panel having thereon linesconstituting the track rails of a diagram of the track layout where thetrack switches and signals are located, manually movable knobs rotatablysupported on said panel on the lines of said track diagram at pointscorresponding approximately with the location of the signals on thetrackway in the field, means associated with each knob for visuallyindicating the position thereof, and actuated by movement of said knob,and means governed by said circuit controller means controlling theclearing of the corresponding signal.

31. In a system for the remote control of poweroperated track switchesand signals on a track layout on a railroad providing various routes fortrain movement, a control panel having thereon lines constituting thetrack rails of a miniature track diagram of said track layout, manuallyrotatable knobs supported by said panel on the lines of said diagram atpoints corresponding approximately with the location of the signals inthe field, means associated with each knob for visually indicating theposition thereof, contacts for each knob each supported by the panel andclosed by movement of said knob to a position in line with the linerepresenting the track, said contacts being opened by movement of theknob to a position crosswise of such line representing the track, saidcontacts being adapted to control circuits for causing clearing of thecorresponding signals.

32. In a system for the remote control of power-operated track switchesof a track layout on railroads providing different routes for trainmovement, a control panel having lines thereon constituting the trackrails. of a miniature track diagram of the track layout, miniatureswitch points pivotally supported on said panel at points correspondingwith the location of the track switches in the field, and having pointedends cooperating with the lines of the track diagram to show graphicallythe different positions of the switch points, electro-magnets foroperating each miniature track switch "to its two different positions, amanually operable control lever on the panel having a contact includedin the control circuit for governing the operation of each track switch,and means for selectively energizing said electro-magnets of eachminiature track switch in accordance with the position of thecorresponding control lever.

33. A control panel for systems having a combined manual and automaticcontrol of poweroperated track switches of a track layout providingvarious routes for train movement comprising, means on the face of thepanel constituting a miniature track diagram of the track layout,manually operable signal controlling knobs supported on said panel onthe lines of said diagram signifying track rails at points correspondingwith the location of the signals in the field, means associated witheach signal knob for visually indicating the position thereof, miniatureswitch points pivotally supported on said panel at points correspondingwith the location of track switches in the field and having pointed endscooperating with the lines of said track diagram to show visually thediiferent positions of the switch points, and electro-magnets foroperating each miniature track switch to its two difierent positions.

34.- In a system for the remote control of power-operated track switchesand signals on railroads, the combination with power-operated switchmachines and their associated signals of a track layout for establishingdifferent routes for train movements, a control panel having thereon adiagram of the track layout, miniature track switches movably supportedon said panel at points corresponding with the location of the trackswitches in the field, manually rotatable knobs supported by said panelon the lines of said track diagram signifying track rails at pointscorresponding approximately with the location of the signals in thefield, means associated with each knob for visually indicating theposition thereof, means for automatically operating said miniature trackswitches to positions to conform with the controlled position of thecorresponding track switches in the field, and means governed bymovement of said knobs for governing the clearing of the correspondingsignals.

35. In a system for the remote control of power-operated switches of atrack layout providing various routes for train movement, thecombination with switch machines operating said track switches, of acontrol panel having lines thereon constituting a miniature trackdiagram of the track layout, miniature track switches pivotallysupported on said panel at points corresponding with the location of thetrack switches in the field and having pointed ends cooperating with thelines of said track diagram to indicate visually the difienent positionsof the switch points, manually operable means on said panel included incontrol circuits for governing the operation of the switch machines forthe several switches of the track layout, and means for automaticallypositioning said miniature track switches on the track diagram inaccordance with the position to which the corresponding switch machinein the field is controlled by said manually operable control means.

SEDGWICK N. WIGHT.

